movable part with an integrated waveguide for an electronics device

ABSTRACT

A movable part for an electronic device which comprises at least two parts that can be moved in relation to each other. The movable part comprises a display for the electronic device and a first conducting plane which is comprised in the display or located adjacent to the display. The first conducting plane comprises a waveguide. The waveguide may be a co-planar waveguide, i.e. a waveguide which comprises a central strip of conducting material surrounded by slots on both sides.

TECHNICAL FIELD

The present invention discloses a movable part for an electronic devicethat comprises at least two parts which can be moved in relation to eachother.

BACKGROUND

Modern electronic devices such as, for example, portable computers(“laptops computers”), or “clamshell” cellular telephones comprise twoparts which can be moved relative to each other, with one of these partscomprising a display, usually a so called LCD (Liquid Crystal Display)or TFT (Thin film Transistor) display. Another example of an electronicdevice with two parts which can be moved relative to each other iscellular telephones where the two parts can slide relative to eachother, as opposed to the rotating parts of the laptop computers orclamshell telephones.

These electronic devices with moving parts will usually comprise atleast one antenna, but will usually have a rather large number ofantennas, since a number of standards or frequency bands need to beaccommodated. Examples of such standards are WLAN, Bluetooth, GPS, GPRS,UMTS etc, as well as different frequency bands which are used indifferent parts of the world.

In addition, there may also be a desire to equip a device with aplurality of antennas in order to obtain diversity reception andpossibly also to take advantage of MIMO (Multiple Input Multiple Output)technology.

In conclusion, it can be stated that modern electronic devices usuallyneed to be equipped with a number of different antennas. Usually, theseantennas are placed in the part of the device which also comprises thedisplay, usually at or around the edges of the device, e.g. on andaround the lid in the case of a laptop computer.

The antennas will be connected to electronics in the device by means ofcables which extend behind the display in order to reach the antennas,each antenna being connected to electronics by at least one cable. Thus,with a large number of antennas, as required by modern devices, therewill also be a large number of cables, and there is a risk of makingerrors when connecting the antennas to the cables.

SUMMARY

As explained above, there is thus a need for a solution by means ofwhich antennas in a moving part in an electronic device can be connectedto electronics in a better manner than previously.

In addition, since the large number of cables leading to and from theantennas involved in modern electronic devices will also becomecumbersome since they are usually installed behind the display of thedevice, the solution should also be more compact than previoussolutions.

Such a solution is offered by the present invention in that it disclosesa movable part for an electronic device which comprises at least twoparts which can be moved in relation to each other, so that the movablepart of the invention is one of said parts.

The movable part of the invention comprises a display for the electronicdevice, as well as comprising a conducting plane which is comprised inthe display or located adjacent to the display.

In the movable part of the invention, the first conducting planecomprises a waveguide. By means of this waveguide, antennas in or aroundthe display can be connected to electronics which are housed in otherparts of the electronic device, and since the waveguide or waveguideswill be housed in one and the same plane, there is little or no risk ofmistakes during installation.

Also, most displays, such as LCD or TFT displays house a conductingplane as a back layer of the display. If this back layer of the displayis used as the conducting layer of the invention, the waveguides can behoused in the display unit as such, thus making the cabling both simplerand of less volume than in previous solutions.

In one embodiment of the invention, the waveguide is a so calledco-planar waveguide, i.e. a waveguide which comprises a central strip ofconducting material surrounded by slots on both sides. Such a waveguidecan easily be created in a back layer of a TFT or LCD display, or in asheet which is housed behind the display.

As has been explained, the waveguide of the invention is suitably usedto obtain a connection between an antenna which is attached to themovable part and electronics such as a send and/or receive module.

These and other advantages of the present invention will become evenmore apparent from the following detailed description of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in more detail in the following, withreference to the appended drawings, in which

FIG. 1 shows an example of a device in which the invention may be used,and

FIG. 2 shows a front view of a first embodiment of the invention, and

FIG. 3 shows a cross section of the device of FIG. 2 along the lineIII-III, and

FIG. 4 shows a version of the embodiment of FIG. 3, and

FIG. 5 shows a front view of a second embodiment of the invention, and

FIG. 6 shows a front view of a third embodiment of the invention, and

FIG. 7 shows a front view of a fourth embodiment of the invention, and

FIG. 8 shows an exploded view of another embodiment of the invention,and

FIG. 9 shows a cross section of the embodiment of FIG. 8, and

FIG. 10 shows a front view of another embodiment of the invention, and

FIGS. 11 and 12 show different cross sections of the embodiment of FIG.10, and

FIG. 13 shows a flow chart of a method of the invention, and

FIG. 14 shows an exploded view of a device in which the in invention isapplied.

DETAILED DESCRIPTION

FIG. 1 shows an example 100 of an electronic device in which the presentinvention may be used. As can be seen in FIG. 1, the device which isused to exemplify the invention is a laptop computer 100 which comprisesa chassis 130 in which there is a keyboard, and also comprises a lid 110which houses a display 120. As indicated by means of a curved arrow, thelid 110 and the chassis may be moved relative to each other; in the caseof the laptop computer they are rotatable with respect to each other.

It should be pointed out immediately that the device 100 shown in FIG.1, i.e. a laptop computer, is merely an example of a device in which thepresent invention may be used, and is in no way intended to restrict thescope of protection of the invention. The invention may be applied in awide variety of electronic devices which have two or more parts that maybe moved in relation to each other, and which comprise a display.

Returning now to the exemplary device of FIG. 1, a display such as theflat kind of display used in most modern electronic devices, e.g. LCD orTFT displays, will usually comprise a back layer which is made of aconducting material. According to the invention, this back layer isutilized in order to house one or more waveguides, as will be shown inthe following. However, if the display as such does not have a backlayer which is conducting, a conducting plate can be arranged behind thedisplay as such. In either case, since the waveguide or waveguides inthe invention are housed in one contiguous layer or sheet, the desiredease of installation will be obtained, as well as the desired “lowbulk”-feature.

FIG. 2 shows a front view of a back layer or conducting layer 200 in afirst embodiment of the invention. In order to facilitate the reader'sunderstanding of the invention, the back layer is shown with twoantennas 210 220, which are attached to the edges of the lid of thelaptop computer of FIG. 1. However, in this embodiment, the antennasneed not be part of the invention.

As is shown, the conducting layer 200 comprises a first and a secondwaveguide 230, 240, which are used to connect the antennas 210 and 220to electronics which may be housed in, for example, the chassis 130 ofthe laptop computer 100 of FIG. 1. It should be pointed out that thenumber of waveguides (and antennas) shown in FIG. 2 and described hereare merely examples; the number can be varied more or less arbitrarily,from one and upwards. Also, each antenna can be connected to more thanone waveguide.

The waveguides 230, 240, are suitably so called coplanar waveguides,i.e. a waveguide which comprises a central strip, shown as W and W′ inFIG. 2, the central strip being surrounded on each side by a slot (shownas S1, S2, S1′, S2′ in FIG. 2. If the slots of the waveguide orwaveguides extend along the entire length of the layer 200, a layer ofnon conducting material may suitably be arranged on one side of thelayer 200, for mechanical reasons.

The antennas 210, 220 may, for example, be connected to the waveguides230, 240, by means of a coaxial contact which has a transition with acentre conductor that contacts the centre strip W, W′, of the respectivewaveguide, or as an alternative, the antennas 210, 220, may be of a moreadvanced kind which can be excited by the centre strip of a waveguide.In such a case, the centre strip of the waveguide is merely extended toallow it to extend into the antenna.

FIG. 3 shows a cross sectional view of the layer 200 of the inventionalong the line III-III shown in FIG. 2. In this view, the design of thewaveguides 230, 240, can be seen even more clearly. As seen here, andalso in FIG. 2, each waveguide comprises a centre strip W, W′, with acertain width, and is surrounded by slots S1, S2; S1′, S2′. Thecharacteristic impedance of the waveguide will be determined by theratio W/(2S+W), where W is the width of the centre conductor, and S isthe width of the slots.

FIG. 4 shows a version 200′ of the back layer 200 of FIG. 3. Thisembodiment 200′ may be used if the slots of the waveguides extendthrough the entire length (or width or breadth) of the back layer, or atleast sufficiently far so as to make the back layer in need ofmechanical stabilization. In such a case, as shown in FIG. 4, a layer ofnon-conducting, electrically transparent material may be arranged on oneside of the back layer.

FIG. 5 shows a back layer 500 of a second embodiment of the invention.In this embodiment, the conducting layer or plane 500 comprises at leastone antenna element, in the example shown in FIG. 5 there are two suchelements 510, 515 shown. As is also shown in FIG. 5, in this embodiment,the waveguides, here shown as 540 and 545, connect to the antennaelement or elements 510, 515.

The antenna elements 510, 515, of the embodiment 500 are suitably socalled patch antennas, i.e. patches which are created in the conductingmaterial of the back layer 500. The antenna elements shown in FIG. 5 areexamples of such patch antennas, with the patches shown in FIG. 5 beingrectangular patch elements. As can be seen in FIG. 5, the patch elementshave been created by making a slot 525, 535, around the area 520, 530,which is intended as the patch. As is also shown in FIG. 5, therespective waveguide 540, 545, of the antenna elements 510, 515,connects to the antenna element by having the waveguide extend a certaindistance into the antenna element. The distance with which the waveguideextends into the antenna element is suitably varied using simulationsand optimization so that good matching is obtained. The width of theantenna element may also be varied for this purpose.

Thus, in the embodiment of FIG. 5, the back layer as such incorporatesone or more antenna elements 510, 515, to which the waveguide orwaveguides 540, 545, connect. As can be realized this embodiment willprovide for an extremely compact antenna design, which will naturally behighly advantageous in electronic devices such as laptop computers,cellular telephones etc.

Regarding the antenna elements 510, 515, of the embodiment 500, therectangular patches shown in FIG. 5 are merely examples of a wide rangeof patch antennas, which as such will be known to the man skilled in thefield, and which can be used in the present invention. Other examples ofsuch patch antennas or patch elements are so called “slot loops”, where,as the name implies, the rectangular shape shown in FIG. 5 is replacedby a round or oval shaped patch which is surrounded by a slot, such asthe slots 535, 525 of FIG. 5.

Regarding the operational frequency and bandwidth of the antennaelements, the length L (shown in FIG. 5) of the rectangles will beproportional to λ/2, where λ is the centre frequency of the frequencyrange in which the patch can operate.

The bandwidth of the patch or patches is determined by the width of thepatch, i.e. the extension of the patch in a direction which isperpendicular to the length. A wider patch will provide a biggerbandwidth, but the length of the patch also needs to be adapted to thewidth, so that a wider patch will become shorter.

FIG. 6 shows another embodiment 600 of the back layer of the presentinvention. In similarity with the embodiments 400 and 500 of FIGS. 4 and5, this embodiment comprises a number of antenna elements, the examplein FIG. 6 comprising three such elements, 610, 615, 620. In theembodiment 600, the waveguide which is formed in the conducting backlayer is shaped into a feeder network 630, which branches out into threebranches 625, 635, 640, in order to connect to the antenna elements ofthe layer. By means of the feeder network 630, the antenna elements canthus be accessed for reception and/or transmission in one single commonpoint, shown as C in FIG. 6. The antenna elements of the embodiment 600may be the same as those described above in connection with thedescription of the other embodiments.

FIG. 7 shows a further embodiment of a back layer 700 of the invention.The embodiment 700 comprises a plurality of antenna elements which havebeen given the same reference numbers, 610, 615, 620, as those of theembodiment in FIG. 6. Also in similarity with the embodiment of FIG. 6,the back layer 700 comprises a feeder network 630 which branches out tothe antenna elements of the layer. However, the embodiment 700 of FIG. 7also comprises receive and/or transmit electronics in the back layer700, here shown as 710, 720.

The role of the transmit and receive electronics can, for example, bemodulation, demodulation, filtering, amplification or conversion betweendifferent kinds of bit streams.

If the receive and/or transmit electronics are incorporated into theback layer 700, as shown in the embodiment 700, this will naturally evenfurther enhance the “low bulk” feature of the present invention.

One way of incorporating electronics into the back layer is tomanufacture IC chips in so called thin film technique, and to thenarrange the chips on the back layer 700, whilst making connection podsand connection leads in the coplanar technology outlined previously inthis text. The chips would then be attached to the pods and/or leads bysoldering.

If send and/or receive electronics 710, 720, are integrated into theback layer 700, the antennas maybe accessed on baseband level or bymeans of a digital bus, shown as 730 in FIG. 7.

Another way of integrating send and/or receive electronics into the backlayer 700 would be to form at least some of the components of thoseelectronics, e.g. semi-conductors and discrete components, directly onthe back layer by means of conventional methods for creating componentsin semi-conducting layers, such as, for example, doping of thesemi-conducting layers if it is desired to form semi-conductorcomponents such as transistors dipoles etc. directly in those layer, andstandard etching techniques may be used for creating connections betweenthe components.

If electronics components are to be integrated into the back layer ofthe invention, as shown in FIG. 7, it may be necessary to have branchesof the feeder network 630 or other conducting leads which cross eachother. This may be the case if, for example, it is desired to connectmore than one antenna element to more than one electronics component. Asolution to letting conductors cross each other will be shown below inconnection with the description of FIGS. 10-12.

Another alternative of the present invention is shown in FIG. 8: thepatches shown in FIGS. 4-7 may, instead of being used as “stand alone”radiation elements, be used to excite radiation elements arranged inanother plane which is arranged spaced apart from the layer in which theexcitation patches are arranged. This second layer may be spaced apartfrom the first layer of the excitation patches by mechanical means suchas spacers, so that there is essentially only air in between the twolayers, or as an alternative, a layer of a standard dielectric materialcan be arranged between the two layers.

Thus, as shown in FIG. 8, the device 800 comprises a first layer 810,which may be a layer of a non-conducting material, on which there isarranged one or more radiating antenna patches 820 in a conductingmaterial. These patches 820 are suitably but not necessarily arranged onthe layer 810 by means of etching.

In addition to the layer 810, the device or enhanced back layer 800 ofthe device also comprises a second layer 830, which is arrangedessentially in parallel to the first layer 810, but spaced apart fromit, as described above.

This second layer 830 comprises one or more patches 850 as described inconnection with FIGS. 4-7 above, with a waveguide feed 840, which isalso designed according to the principles described above.

The first 810 and second 830 layers are not only arranged essentially inparallel to each other, but also so that the exciting patch 850 mayexcite the patch 820 of the first layer.

Naturally, the first and second layers of the invention can comprisemore than one pair of exciting/radiating patches, the number of suchpairs can be varied more or less arbitrarily.

FIG. 9 shows a cross section of a version 900 of the design of FIG. 8,taken along the line IX-IX shown in FIG. 8. As can be seen in FIG. 9,the design 900 comprises the first 810 and second 830 planes of FIG. 8,spaced apart by conventional non-conducting means (not shown in FIG. 9)such as spacers or dielectric layers. In addition, the first layercomprises the antenna element c 820 shown in FIG. 8. The antenna element820 is fed by the patch 850 of FIG. 8.

As is also shown in FIG. 9, the patch 850 is surrounded by two slots,thus making it a co-planar element.

FIG. 10 shows a front view of another embodiment 1000 of the invention,As shown, this embodiment 1000 comprises four radiation elements 1010,1020, 1030, 1040, with respective feed lines 1011, 1021, 1031, 1041,which can be accessed at access points 1012, 1022, 1032, 1042.

As seen in FIG. 10, the feed lines 1011, 1021, 1031, 1041, cross eachother. How this can be accomplished will be shown in FIGS. 11 and 12,which show cross-sections of the device 1000 along the lines XI (FIG.11) and XII (FIG. 12) shown in FIG. 10. However, before embarking on adescription of those figures, it can be pointed out that the radiationelements 1010 and 1040 are excited by patches which terminate the feedlines 1011 and 1041, said feed lines 1011, 1041, and their excitingpatches being designed in the co-planar technology which has beendescribed previously in this text.

The exciting patches and the coplanar feed lines 1011, 1041, arearranged in a plane below (as seen “into” the paper of FIG. 10) theradiation elements, which will be show in FIGS. 11 and 12.

The radiation elements 1020, 1030 with their feed lines 1021 and 1031are designed in microstrip technology, which is a technology well knownto those skilled in the field, and which utilizes a conductor placed ata certain distance from a conducting ground plane. The feed lines 1021,1031 of the radiation elements 1020, 1030, are located in the same planeas the radiation elements, and the radiation elements 1020, 1030, have apatch placed below them in order to increase the bandwidth of theradiation elements.

Thus, FIG. 11 shows the device 1000 of FIG. 10 in a cross section alongthe line XI-XI shown in FIG. 10. In FIG. 11, the patches which excitethe radiation elements 1010, 1040, and which terminate the feed lines1011, 1041 are shown as 1013 and 1043, surrounded by isolating slots.

The microstrip patches 1020 and 1030 are also shown in FIG. 11, with theaforementioned patches 1023, 1033, arranged below them, which is done inorder to increase the bandwidth of the radiation elements 1020, 1030.

In order to facilitate comparison with FIG. 12, two lines, A and B areshown in FIG. 11, with the two lines intended to show different layersof the device 1000.

FIG. 12 shows the device 1000 of FIG. 10 in a cross section along theline XII-XII shown in FIG. 10. Here, in the “B-layer” we see the feedlines 1011 and 1041, and, as mentioned previously, the feed lines 1011and 1041 are designed in the co-planar technique described above,something which can be seen clearly in FIG. 12, since each of the feedlines 1011 and 1041 exhibits a centre strip surrounded by a slot on eachside.

In FIG. 12, in the “A-layer”, the feed lines 1021 and 1031 are alsoshown. As mentioned, these feed lines are designed in so calledmicrostrip technology, in which there is a conductor placed at adistance from a ground plane. The feed lines 1021, 1031 are designed sothat their conductor is placed in a separate layer, i.e. the “A-layer”,at a distance from the “B-layer” in which the co-planar waveguide feedlines 1011 and 1041 are arranged, so that the conducting plane in whichthe co planar waveguides are arranged can serve as ground plane for themicrostrip lines 1021 and 1031.

FIG. 13 shows a rough flow chart of a method 1300 of the invention.Steps which are options or alternatives are shown with dashed lines.Thus, the method 1300 of the invention is a method for assembling amovable part for an electronic device such as the one 100 shown in FIG.1, i.e. a device which comprises at least two parts which can be movedin relation to each other, and the method comprises the step ofarranging in said movable part a display, as shown in step 1310, for theelectronic device, and also comprises arranging a first conductingplane, “Plane 1”, as shown in step 1015, a plane which is arranged in oradjacent to the display.

As indicated in step 1320, the method also comprises arranging awaveguide in the first conducting plane.

Step 1325 indicates that the waveguide may be a so called co-planarwaveguide, i.e. a waveguide which comprises a central strip ofconducting material surrounded by slots on both sides.

As shown in step 1340, the waveguide can be arranged in the firstconducting plane so that a connection is obtained between an antennawhich is attached to the movable part and a contact for a send and/orreceive module.

Step 1330 indicates that the first conducting plane may additionally bemade to comprise at least one antenna element which the waveguide in theconducting plane connects to.

The “antenna step” 1330 is also meant to indicate that according to theinventive method, the first conducting plane may be made to comprise aplurality of antenna elements. In such a case, the inventive waveguidecan be formed into a feeder network, so that the antenna elements may beaccessed from a common point in the first conducting plane.

Step 1335 shows that at least one of the antenna element(s) may be madeas a patch antenna of rectangular, circular or oval shape.

One method for making the antenna elements is indicated in step 1050,which shows that the antenna element or elements can be etched into thefirst conducting plane.

Step 1355 shows that micro strip technology may be used in the method ofthe present invention, in which case the movable part is made to alsocomprise a second conducting plane, which is arranged adjacent to thefirst conducting plane, so that a radiation element in the firstconducting plane can excite an antenna element in the second conductingplane. In this way, the movable part is made to comprise a micro stripantenna, formed by the first and second planes.

FIG. 14 shows an exploded view of a display 1400 for a portable computerin which a “rear plate” of the invention is used. The layers or plates1410 and 1430-1490 are used for the display and will thus not beexplained here. However, the display 1400 also includes a conductinglayer 1420, which is used for the invention. As shown in FIG. 14, in thelayer 1420 there are two co-planar waveguides formed, the grooves orslits of one being shown as 1417 and 1418. Each of the co-planarwaveguides connects to an antenna, one of which is shown as 1416 in FIG.14. The antennas may be formed in the conducting layer, in one of theways described previously in this description, or they can be arrangedin connection to the conducting layer, which is the alternative that isshown in FIG. 14.

In addition, as shown in FIG. 14, the conducting layer 1420 may rest ona layer of non-conducting material 1415, if it is desired to addstability to the layer 1420.

The invention is not limited to the examples of embodiments describedabove and shown in the drawings, but may be freely varied within thescope of the appended claims. For example, other kinds of waveguidesthan co-planar may be formed in a conducting plane of the invention,such as for example so called slot lines, which, as the name implies,comprise only a slot, as opposed to the co-planar waveguide's conductingstrip surrounded by two slot lines.

1. A movable part for an electronic device which comprises at least twoparts which can be moved in relation to each other, said movable partcomprising a display for the electronic device as well as a firstconducting plane which is comprised in the display or located adjacentto the display, the movable part being characterized in that the firstconducting plane comprises a waveguide.
 2. The movable part of claim 1,in which the waveguide is a co-planar waveguide that comprises a centralstrip of conducting material surrounded by slots on both sides.
 3. Themovable part of claim 1, in which the waveguide is used to obtain aconnection between an antenna which is attached to the movable part anda send and/or receive module.
 4. The movable part of claim 1, in whichthe first conducting plane additionally comprises at least one antennaelement to which the waveguide connects.
 5. The movable part of claim 4,comprising a plurality of antenna elements, and in which the waveguideis formed into a feeder network, so that the antenna elements may beaccessed from a common point in the first conducting plane.
 6. Themovable part of claim 4, in which at least one of the antenna elementsis a patch antenna of rectangular, circular or oval shape.
 7. Themovable part of claim 4, in which the antenna element or elements areetched into the first conducting plane.
 8. The movable part of claim 1,further comprising a second conducting plane arranged adjacent to thefirst conducting plane, so that a radiation element in the firstconducting plane acts so as to excite an antenna element in the secondconducting plane, so that the movable part comprises a micro stripantenna, formed by the first and second planes.
 9. The movable part ofclaim 1, being a movable part implemented in one of a group consistingof: A portable computer, a “laptop” computer, A personal digitalassistant, a “PDA”, A cellular telephone.
 10. A method for assembling amovable part for an electronic device which comprises at least two partswhich can be moved in relation to each other, the method comprisingarranging in said movable part a display for the electronic device aswell as arranging a first conducting plane in or adjacent to thedisplay, the method being characterized in that it comprises arrangingin the first conducting plane a waveguide.
 11. The method of claim 10,according to which the waveguide is a co-planar waveguide that comprisesa central strip of conducting material surrounded by slots on bothsides.
 12. The method of claim 10, according to which the waveguide isarranged in the first conducting plane so that a connection is obtainedbetween an antenna which is attached to the movable part and a sendand/or receive module.
 13. The method of claim 10, according to whichthe first conducting plane is additionally made to comprise at least oneantenna element to which the waveguide connects.
 14. The method of claim13, according to which the first conducting plane is made to comprise aplurality of antenna elements, and according to which the waveguide isformed into a feeder network, so that the antenna elements may beaccessed from a common point in the first conducting plane.
 15. Themethod of claim 13, according to which at least one of the antennaelements is made as a patch antenna of rectangular, circular or ovalshape.
 16. The method of claim 13, according to which the antennaelement or elements are etched into the first conducting plane.
 17. Themethod of claim 10, according to which the movable part is made toadditionally comprise a second conducting plane which is arrangedadjacent to the first conducting plane, so that a radiation element inthe first conducting plane can excite an antenna element in the secondconducting plane, by means of which method the movable part is made tocomprises a micro strip antenna, formed by the first and second planes.